Chalmers BP, Elmasry SS, Kahlenberg CA, et al. - This research sought to distinguish the effect of joint line elevation on mid-flexion laxity. Six computational knee models with cadaver-specific capsular and collateral ligament properties were implanted with a posterior-stabilized (PS) total knee arthroplasty. Researchers assessed coronal laxity (the sum of varus and valgus angulation with respective maximum moments) throughout flexion. The results showed that with joint line elevation in primary PS total knee arthroplasty, coronal laxity peaks early (about 16°) with a maximum laxity of 8°. It has been considered that surgeons should restore the joint line whether possible; nevertheless, whether joint line elevation is necessary, the assessment of coronal laxity at 15° to 30° of knee flexion was recommended to evaluate for mid-flexion instability. There is a need for further in vivo studies to understand whether this mid-flexion coronal laxity has negative clinical implications.